To me, London is the best city in the world. Yet it is not a city in control of its own destiny...compared with the cities with which we compete, London has very little say over its future. Only seven per cent of the taxes raised from London taxpayers and businesses is spent by London’s government — compared with 50 per cent in New York. The next Labour government is committed to changing this.

Khan says a future Miliband of Number 10 would “devolve more power and funding to every layer of London government”. But Labour is not marching down Devolution Street alone. Its company includes London Councils, which represents the capital’s 33 local authorities, and Boris Johnson, who we must thank for creating the London Finance Commission, which recommended that a “suite of property taxes” raised in the capital should be collected and spent there too rather than sent elsewhere via Whitehall. The Commission’s report has become a benchmark text.

Such enhancements of London’s autonomy would continue a trend that began with the founding of the Greater London Authority and the mayoralty, effective from 2000. Khan reminds us that this was a Labour achievement - one which restored to London its own government tier following Margaret Thatcher’s abolition of the Greater London Council in 1986 (too much defiance from that Ken Livingstone across the Thames at County Hall).

Yet the coalition has moved in the same direction: the Localism Act (2011) gave important new housing and planning powers to London mayors, enabling Johnson to more directly shape major redevelopment projects, including through mayoral development corporations - hence the London Legacy Development Corporation which controls the evolution of the Olympic Park and its surrounding areas.

Since then, Johnson has joined with the capital’s local authorities in asking central government to let London govern itself still more. In April, they proposed a Growth Deal for London, which echoed the London Finance Commission’s property taxes call, asked for more public land to be put at the capital’s disposal for housing and, supported by the Federation of Small Businesses, requested the de-centralisation of employment and careers services.

Johnson says this is essential if London is to meet the transport, housing and employment needs of a soaring population and to “see that success and gains are evenly shared across the capital”. London Councils chair Jules Pipe, also the Labour mayor of Hackney, placed the growth deal bid in the national context: “I believe London’s future within a prosperous United Kingdom demands greater freedom to build on our success for the benefit of the entire country.”

These very sentiments, of course, trigger earthquakes of indignation rather than waves of gratitude elsewhere in these lands. “What use is a more powerful London to us?” non-Londoners complain. The capital hogs everything already, they say: all that transport subsidy; all that global capital; and it’s stealing all our clever children too. One side hails London as the glorious driving force of the entire UK economy, the other damns it as sucking the life out of everywhere that doesn’t speak Estuary English.

It isn’t quite that simple. Pros and cons flow in both directions, and government policy cuts both ways too. For one thing, parts of London - especially its poorer parts - have been hit hard by local government spending cuts. Imagine the difference it could make to those parts of the city where property prices have soared yet many people on low incomes still live - Camden, Islington, Southwark, Hackney and more - if the local council got it hands on local stamp duty. Fiscal devolution could help mitigate the harm caused by austerity.

For another, the best answer to the “London problem” may be for other UK cities to be given more of the sorts of muscle London enjoys. In other words, not a shift of power and resources away from London to everywhere else, but a shift away from Whitehall to Manchester, Liverpool, Bristol, Birmingham and so on.